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Why aren’t we talking more about airborne transmission?

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Re: Why aren’t we talking more about airborne transmission?

#251

Post by everdrive »

lmilcin wrote: post #208
prutschman wrote: post #157

Earlier quoted context omitted.

I don't see what was incorrect about the parent. It goes on to say "However, there are microdroplets which stay in the air for 30+ minutes depending on the air currents." It sounds like you're both in agreement that large droplets fall quickly to the ground, and that with COIVD the longer-lasting micro-droplets are a relevant factor. Am I missing a subtlety?

There are no "microdroplets" which stay in the air for "30+" minutes. First, water DRIES OUT unless the humidity is very close to 100% which is relatively rare in western countries. The smaller droplet the faster this happens. Put a very, very small droplet on a flat surface like glass. Observe it disappear within couple of minutes. Then imagine that a smaller droplet is just larger droplet closer to drying out. Volu…

I appreciate the distinction you're making here. I don't have enough facts to prove or disprove it.

But, I'd like to ask: are you suggesting that aerosolized droplets cannot be seriously spreading this disease because they will evaporate almost instantly?

I ask because there is quite a bit of research suggesting that aerosolized droplets are spreading the disease, and can hang int the air for a substantial period of time. Do you think this is wrong? If it is wrong, why do you believe people are suggesting aerosolized transmission?

Re: Why aren’t we talking more about airborne transmission?

#252

Post by dang »

droopyEyelids wrote: post #122
jennyyang wrote: post #32

After this pandemic, doctors and scientists are going to have to come up with more media-friendly terms from now on. The problem is that "airborne droplets" and "airborne" sound too similar and it's very hard for regular people to understand what that means. "Airborne droplets" means that viruses need saliva to transmit between people. "Airborne" means that the virus only needs dust particles to transmit to other peo…

The WHOLE POINT of the article is to educate you about the difference between droplets (ballistic) and aerosols (behave like a gas). It doesn't look like you, or the people replying to you read the article. And thats a shame, because you're exactly the type of person who the author is trying to educate.

Please read and follow the site guidelines. You broke several of them here, and have been doing so elsewhere also.

https://news.ycombinator.com/newsguidelines.html

Re: Why aren’t we talking more about airborne transmission?

#253

Post by SkyPuncher »

timr wrote: post #228
SkyPuncher wrote: post #118

Earlier quoted context omitted.

> If someone with coronavirus sneezes in a room, the large heavy droplets will quickly fall to the ground. This is the slightly incorrect part with COVID. Traditionally, this would be an appropriate description for other droplet transmission (like the flu). However, it seems COVID has an above average ability to survive in extremely fine droplets - think mist-sized particles that CAN float in the air for an extended…

"However, it seems COVID has an above average ability to survive in extremely fine droplets - think mist-sized particles that CAN float in the air for an extended period of time (given the right circumstances)." This is one of those "facts" that is often repeated, but which has little actual evidence if you bother to look for it. The WHO has been consistent that aerosol transmission of the virus is a theory with litt…

> although aerosolization in medical settings where aerosol generating procedures are used is also another possible mode of transmission

I'm married to a physician and have been primarily following this through the eyes of her and her peers. In an acute care setting, aerosolization is a huge concern. It's a big factor between being able to get away with a surgical mask/face shield and requiring significant PPE.

In daily life, this probably isn't a huge concern (or a significant means of transmission at a public health level).

Re: Why aren’t we talking more about airborne transmission?

#254

Post by misanthropian00 »

CogentHedgehog wrote: post #168
misanthropian00 wrote: post #65

Earlier quoted context omitted.

More emphasis on better masks that actually might prevent aerosol transmission and less emphasis on 6 foot distancing because such things matter little under aerosol conditions where air flow patterns dominate transmission. Also much more emphasis on outdoor vs indoor activities. So no it is not really the same guidance.

Your claims do not reflect what the article and the evidence it cites show. To quote: > Cowling told me that it’s better to call these “short-range aerosols,” as that communicates the nature of the threat more accurately: Most of these particles are concentrated around the infected person, but, under the right circumstances, they can accumulate and get around. This is the precise opposite of your claim that 6 foot di…

Well first of all there is little evidence on both sides of the argument here. There isn't much evidence in favor of aerosol transmission and there isn't much evidence against it either. I would hope that more research can be done on this matter.

Perhaps I worded my statement poorly. Let me try to be more precise about the idea I was trying to express. If COVID really is more aerosol infectious than we have been assuming then the 6 foot distancing would matter much less in comparison because if a cloud of infectious COVID droplets is whirling in the air currents that effect will tend to dominate in the sense that your exact location relative to the COVID+ source is no longer a direct causal factor. Yes of course being farther away makes it less likely that you will be in the path of a relatively short range aerosol cloud but the important thing in that circumstance is not to be in its path and just being farther away in the same room may not be enough to avoid it.

I don't deny that if someone with COVID coughs directly in your face which apparently was considered the dominant transmission vector at first you are also likely to be infected especially if you are not fully and properly masked and goggled. That must happen sometimes. Of course being at least 6 feet away from the closest person is a good thing. It is just the assumption that that is enough to keep people safe from COVID that should be questioned more.

Anyway my quibble with your post was the part about the guidelines being the same. They aren't really. The difference may be slight, but it could be critical.

Re: Why aren’t we talking more about airborne transmission?

#255

Post by CogentHedgehog »

DoingIsLearning wrote: post #201
CogentHedgehog wrote: post #178

There's one key paragraph buried in the article that will help a lot of people: > However, to date, there is also no evidence of truly long-range transmission of COVID-19, or any pattern of spread like that of measles. Screaming “it’s airborne!” can give the wrong impression to an already weary and panicked public, and that’s one reason that some public-health specialists have been understandably wary of the term, so…

> people can get infected further away than with larger droplets Minor nitpick, you can think of aerosol transmission as plume of virus particles. Technically you can get infected long after the carrier has left a closed room, at which point the concept of being "further away" stops applying.

That's true, in this case "further away" is a 4-dimensional distance vector (it includes time). :D

Re: Why aren’t we talking more about airborne transmission?

#256

Post by throwaway_pdp09 »

jennyyang wrote: post #120
jtbayly wrote: post #68

Earlier quoted context omitted.

> we would have to implement extremely strict lockdowns... if we assume that the goal is not to flatten the curve but to completely stop the virus in its tracks. Most people and countries don't have this goal. Edit: To those downvoting, I'll just say that my statement is factual, so argue the facts. Long-term, we want a vaccine, yes. In the meantime, most people and countries are simply not willing to do what it take…

If the virus were truly airborne, which it isn't, then simply walking through an empty room could get you infected. The levels of people getting infected, and subsequently getting hospitalized would be far worse than the worst scenes we saw in Italy and NYC. Lockdowns absolutely would have been mandatory for months upon months. Coronavirus is not by itself a tremendously deadly disease. The problem is how infectious…

WTF is going on here?

You claim "If the virus were truly airborne, which it isn't" yet provide no evidence.

But looking at you history you have provided exactly evidence that it is airborne "Video showing microdroplets suspending in air (vimeo.com)" a few months ago (https://news.ycombinator.com/item?id=22776194)

And to quote from another commenter "The part showing how a single cough can create a room-wide cloud of virus that lingers for 20+ minutes in spaces with poor circulation was especially enlightening."

Having watched the vid I can confirm that's what they show, at least as a simulation.

Even the main article says (I'm re-quoting from another of my posts): "There is a big dispute in the scientific community, however, about both the size and the behavior of these particles, and the resolution of that question would change many recommendations about staying safe. Many scientists believe that the virus is emitted from our mouths also in much smaller particles, which are infectious but also tiny enough that they can remain suspended in the air, float around, be pushed by air currents, and accumulate in enclosed spaces" which directly opposes what you say.

How is your parent post not either plain wrong or deliberately sowing confusion? I'm flagging you.

Re: Why aren’t we talking more about airborne transmission?

#257

Post by xsmasher »

throwaway_pdp09 wrote: post #188
jennyyang wrote: post #120

Earlier quoted context omitted.

If the virus were truly airborne, which it isn't, then simply walking through an empty room could get you infected. The levels of people getting infected, and subsequently getting hospitalized would be far worse than the worst scenes we saw in Italy and NYC. Lockdowns absolutely would have been mandatory for months upon months. Coronavirus is not by itself a tremendously deadly disease. The problem is how infectious…

> If the virus were truly airborne, which it isn't why do you say this? The article is saying otherwise, quite literally "The coronavirus reproduces in our upper and lower respiratory tracts, and is emitted when we breathe, talk, sing, cough, or sneeze" > then simply walking through an empty room could get you infected You're presuming it has to be empty. If you walked through a full room without touching anyone or a…

You don't seem to be engaging with the "airborne on droplets" vs "airborne aerosol" vs "airborne on dust" discussion that spawned this subthread.

Re: Why aren’t we talking more about airborne transmission?

#258

Post by aantix »

highmastdon wrote: post #133
aantix wrote: post #33

Earlier quoted context omitted.

Why wasn't there a large spike with the recent protests in the participating demographic? https://www.forbes.com/sites/tommybeer/2020/07/01/research-d... The chants "no justice, no peace"? "I can't breath"? Those were clear chants. Everyone breathing on each other while chanting. Unencumbered by a mask.

I think a key part is also the dose in which you get infected that leads to illness. When you're in the open air, breathing and chanting, the dose of the virus is so low, that the immune system can easily defend against it. Also, the virus doesn't kill most people, the human immune (over)reaction does. This is my laymen's way of describing a (deadly) course of the virus and disease. 1.1. person breaths in micropartic…

Regarding [5], where is the disagreement on the effectiveness of HCQ + Zinc + Azithromycin?

Overwhelmingly the news has been negative.

The above doesn’t appear to include all of the research.

Re: Why aren’t we talking more about airborne transmission?

#259

Post by dorgo »

scubbo wrote: post #160
DoofusOfDeath wrote: post #113

Earlier quoted context omitted.

> Edit: To those downvoting, I'll just say that my statement is factual, so argue the facts. I wonder if the downvotes were caused by the phrasing of this statement: > Most people and countries don't have this goal. At first I thought you were saying that people didn't actually want to stop the virus in its tracks. It took me a minute to realize that you're saying people have accepted full-stoppage-in-tracks as being…

> At first I thought you were saying that people didn't actually want to stop the virus in its tracks. No, I think that's precisely what they were saying. I don't think that this is unattainable - I think it would have a greater economic cost, particularly to the wealthy, than many countries are willing to bear. It's not unattainable - it would cost them more than those lives are perceived as being worth. Big concept…

It's not only economic cost. To get results like in china you have to be (like) china. It's easy to sell drastic measures to the population if the infection (and death) numbers look scary. But if the numbers stagnate at low values nobody is going to accept drastic measures. You would need to fight against your own population to stop the virus altogether. And even if you achive this, the virus will return (tourist/travelers).

Re: Why aren’t we talking more about airborne transmission?

#260

Post by egberts »

lmilcin wrote: post #208
prutschman wrote: post #157

Earlier quoted context omitted.

I don't see what was incorrect about the parent. It goes on to say "However, there are microdroplets which stay in the air for 30+ minutes depending on the air currents." It sounds like you're both in agreement that large droplets fall quickly to the ground, and that with COIVD the longer-lasting micro-droplets are a relevant factor. Am I missing a subtlety?

There are no "microdroplets" which stay in the air for "30+" minutes. First, water DRIES OUT unless the humidity is very close to 100% which is relatively rare in western countries. The smaller droplet the faster this happens. Put a very, very small droplet on a flat surface like glass. Observe it disappear within couple of minutes. Then imagine that a smaller droplet is just larger droplet closer to drying out. Volu…

Ammonia vapor has the pH level to carry the SARS-CoV-2 like a very very long time.
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